Built‐In Electric Field at the Heterojunction of MnMoO₄@1T‐MoS₂ to Enhance the Electrochemical Storage Capacity in all Quasi‐Solid‐State Supercapacitors

Abstract Heterostructure construction is a strategic approach to boost electrode performance for high‐efficiency supercapacitors. Herein, a coreshell heterostructure of MnMoO 4 @1T‐MoS 2 was synthesized and evaluated in both symmetric and asymmetric configurations. The heterojunction between these materials generates a built‐in electric field, which significantly enhances conductivity and accelerates charge transport. In addition, the core‐shell structure reduces the volume expansion and restacking of nanoflakes, providing high stability and active sites. Density Functional Theory (DFT) calculations were carried out to explore the theoretical properties of MnMoO 4 @MoS 2 , revealing a strong built‐in electric field of 1.072 VÅ−1 and a remarkably high quantum capacitance (CQ) of 387.06 µF cm −2 at −1 V. The MnMoO 4 @MoS 2 SSC exhibits a specific capacitance (C_sp) of 319 F g−1 at a current density of 1 A g−1 with a cyclic stability 87.9% after 10000 cycles. Furthermore, it delivers a high Ed of 46 Wh/kg with a Pd of ≈653 W kg−1. Meanwhile, the asymmetric capacitor shows a high of C_spof ≈173 F g−1, with a high Ed of ≈51 Wh kg−1 and a Pd of ≈720 W kg−1. The findings indicate that this composite material possesses significant promise as an electrode material for energy storage applications.